Crankcase draining unit



Nov. 26, 1963 w. E. HOCH 3,112,012

' CRANKCASE DRAINING mm Filed March 25, 1960 3 Sheets-Sheet 1 Nov. 26,1963 w. E. HOCH 3,112,012

QRANKCASE DRAINING UNIT Filed March 25. 1960' s Sheets-Sheet 2 T-H p2&6: 3a

Nov. 26, 1963 w. Hoc 3,112,012

CRANKCASE DRAINING UNIT Filed March 25, 1960 5 Sheets-Sheet 3 UnitedStates atent ice eni ma CRANKCASE DRAWENG UNET Woodrow E. Hash, 132i?Westmoor, Winnetka, ill. Fiied ltiar. 23, 1960, Ser. No. 110% 7 Claims.(ill. l841.5)

This invention relates to a rotary vane displacement pump. it isespecially directed to a drainage unit for the rapid, mechanicaldraining of lubricating and industrial oils contained in oil sumps.

In using various types of lubricating and industrial oils, the oil isstored or located in a suitable oil sump from which it is pumped for useor into which the mechanical equipment is dipped for proper lubricationthereof. Usually, the sumps are placed in locations on the equipmentwhich makes the draining of the oil therefrom a difiicult and sometimesdangerous operation. For example, in the draining of lubricating oilfrom automotive crankcases, it is desirable that the engine be operatedfor a time previous to the drainage in order that the lubricating oilcan be heated and thereby made less viscous. In the removal of the oilfrom the crankcase, it is necessary to elevate the automobile to aposition so that the service station attendant or mechanic can haveready access to the crankcase drain plug. Frequently in the removal ofthe drain plug, the hot oil is splashed on the attendant and seriousburns can occur. In other installations, the crankcase or oil sump isnot conveniently located and it is sometimes necessary to dismantleportions of the equipment in order to have ready access to the oil sump.

Becaues the problem of dnaining automotive crankcases or other types ofoil sumps is burdensome, various techniques have been employed forremoving the oil from the oil sumps. For example, in the case ofautomotive crankcases, pumping equipment has been designed wherein theinlet tube of the pump is inserted through the oil level dip-stick holeinto the crankcase in order that the oil can be pumped therefrom. Thisis not a satisfactory arrangement because the dip-stick holes are smalland in certain types of engines have a tortuous path through which it isdiificult to pass the inlet tube of the pumping unit. On other types ofequiment, the sump may be so positioned that it is difficult to insertan inlet tube into the sump tank for the removal of the oil. In

' addition, in certain types of equipment, such as automotive vehicles,during the period between crankcase draining, the oil is subjected tooperating conditions whereby sludge in the form of solid carbonaceousparticles, sand, metal abrasions and the like occur in the lubricatingoil. Because the crankcase is in a substantially static condition duringthe draining of the oil therefrom, the sludge particles precipitate tothe bottom of the crankcase and remain there, so that even though uponrefilling the crankcase with fresh oil, the sludge particles are stillpresent within the crankcase.

According to this invention, there is provided an oil sump drainage unitemploying the rotary vane displacement pump. The rotary pump isconstructed so that the operation of the pump not only will pump the oilfrom the sump but will also induce vibrations during the pumping cyclewhich are transmitted to the oil sump by means of a substantially rigidconduit interconnecting the inlet side of the pump and the oil sump. Thevibration induced by the operation of the pump produces a mixing actionin the oil pool such that the sludge particles are agitated andsuspended within the oil during the draining period therebyfacilitataing the removal of the sludge particles. In addition, therotary pump is provided with a depressed area around outlet port whichpermits the sludge particles received into the pump chamber to bereadily swept therefrom by the impelling action of the pump. Thisprevents sludge particles from being retained in the pump chamber andcausing the jamming of the impeller vane assembly. The depressed areaalso functions as a reservoir to retain a small amount of oil duringperiods of pumping inactivity. Thus, the oil remaining insures thepositive priming of the pump during the next pumping cycle.

Referring to the drawings, FIGURE 1 illustrates a typical installationof the oil sump drainage unit of this invention installed in the enginecompartment of an automotive vehicle for the purpose of facilitatingdrainage of the engine crankcase. An electrical interlock system isschematically shown which prevents operation of the drainage unit whilethe engine is operating or the crankcase is substantially empty.

FIGURE 2 is a cross-sectional side view of a specific embodiment of theoil sump drainage unit of this invention taken along line 22 of FIGURE 6with the electric drive motor being shown in a fragmentary view and withthe cover plate enclosing the gear housing and the pinion rive gearremoved Breakaway views of the pump housing illustrate the mounting ofthe worm gear within the pump housing and its connection to the motor.

FIGURE 3 is a fragmentary view similar to that of FIGURE 2 taken alongline 33 of HGURE 6, showing the pump casing with the gear housing coverremoved and showing pinion drive gear in place.

FIGURE 4 is a fragmentary cross-sectional view taken along line 4-4 ofFIGURE 6 showing the pump casing with the pump housing cover and pumpimpeller removed.

FIGURE 5 is a crosssectional side view of the pump assembly of thisinvention taken along line 55 of FIG- URE 6 showing the position inletand outlet lines of the drainage unit in relationship to the pumpchamber and impeller hub.

FIGURE 6 is a fragmentary transverse cross-sectional end view of the oilsump drainage unit.

FIGURE 7 is an enlarged fragmentary cross-sectional view taken alongline 7-7 in FIGURE 5 of the impeller hub and vane assembly employed inthe drainage unit.

FIGURE 8 is an enlarged fragmentary view taken along line 8-8 in FIGURE6 showing an illustrative coupling means for interconnecting the piniondrive gear with the impeller hub of the oil sump drainage unit.

In the oil sump drainage unit of this invention a rotary vanedisplacement pump employing a single pair of opposed impeller vanesmounted in side-by-side relationship in a slotted impeller hub areemployed as the pumping elements of the subject drainage unit. Theimpeller vanes are biased outwardly from each other into contact withthe side wall of the pump chamber. A suitable drive means is employed toeffect the rotation of the pump im peller within the pump chamber toproduce a pumping action. In the rotary vane displacement pump, the impeller hub is in tangential contact with the side wall of the pumpchamber at the so-called null point to produce a lunate pump chamber. Inorder to induce the desired vibratory effect by the action of the pump,the inlet port of the pump chamber is angularly displaced from the pointof tangential contact or null point between the pump chamber side walland the impeller hub. This displacement produces a surge mistiming ofthe pump cycle which is quantitatively determined by the amount ofvacuum produced by the impeller vane travelling from the point oftangential contact to the point of opening of the inlet port. On theoutlet side of the pump, there is provided a depressed area adjacent theoutlet port into which any sludge particles pumped from the oil sump canbe swept and removed from the pump chamber by the flushing action of thepumped oil. This prevents any sludge particles from being retained inthe pump chamber which would cause jamming of the impeller hub andprevent its rotation. The depressed area also permits the pump to selfprime by retaining a small amount of oil therein.

Referring to the drawings, it will be seen that the specific embodimentof the oil sump drainage unit of this invention drawn to double scalecomprises an electrical motor 10, to which is integrally connected thepump component 11 of the drainage unit. The pump component comprises agear housing 12 upon which are integrally mounted brackets 13 and 14laterally extending there from in order to permit attachment of thedrainage unit to the housing 15 of electrical motor 10. The gear housing12 also serves as a support means for worm gear 16 which is journaledwithin pump housing 12 by means of suitable bearings 17 and 18 which areinstalled into opposed openings 19 and 20 provided in the pump housing12. Worm gear 16 is connected to drive shaft 17 of electrical motor 10by means of a suitable coupling 21. As shown a D-shaped slot 21 isprovided in the coupling 21 which engages the similarly shaped terminalend of shaft 17. A cap 22 is employed to enclose bearing opening 19 inorder to keep out dust, dirt and the like. Interposed between oneterminal end of shaft 23 of Worm gear 16 and cap 22 is a ball bearing 24which functions as a thrust hearing when the drainage unit is operatedwith the worm gear in a vertical position. The other shaft 25 of wormgear 16 is also protected from dust, dirt and the like by means of atubular enclosure 26 which coaxially extends between electrical motorhousing 15 and gear housing 12. The end of tubular enclosure 26 seatswithin a groove 27 provided by hearing 18 and opening 20. A further sealof this joint is effected by means of an O-ring 23 which surrounds thejoint between gear housing 12 and tubular enclosure 26 and fits into asuitable annular groove provided in the surrounding wall of gear housing12.

Referring to FIGURE 6, it will be noted that the outer face of gearhousing 12 is provided with a concavity 29 which surrounds circularpocket 30 which is employed as a bearing surface for shaft 31 of thepinion drive gear 32. Fitted within cavity 29 and surrounding shaft 31is a spring washer 33 which comprises as shown in FIGURE 2 a pluralityof oblique radial faces 34 which bear against the outer face of piniondrive gear 32 and urge it into interconnection with impeller hub 35, aswill be hereinafter discussed. 1

Worm gear 16 and pinion drive gear 32 form a speed reduction drive fordriving impeller hub 35 at a suitable speed by means of electrical motor10 which normally will rotate at a speed in excess of the desired speedof rotation of the pump unit. Pinion drive gear 32 is coupled toimpeller hub 35 by means of a coupling flange 36 comprising an annularflange 37 secured to the interface of pinion drive gear 32 by suitablefastening means 38. Integral with flange 37 is a circular boss 39 whichhas mounted on the outer face thereof a pair of diametrically opposedteeth 40 and 41. Similarly, impeller hub 35 has on the inner facethereof adjacent the face of circular boss 39 a pair of diametricallyopposed teeth 42 and 43.

To couple impeller hub 35 to circular boss 39, a coupling washer 4-4,having disposed in the face thereof a cruciform slot is utilized. Theteeth 40 and 41 on the face of circular boss 39 are displaced 90 withrespect to the teeth 42 and 43 on the face of impeller hub 35. In thisposition, the teeth will register with the cruciform slot 45 provided incoupling washer 44. This type of coupling is employed in theillustrative embodiment in order to compensate for any minormisalignments which might occur during the manufacture of the pumpingunit and affect the exact coaxial alignment of pinion drive gear 32 andimpeller hub 35.

Impeller hub 35 is disposed within lunate pump chamber 59 which isformed by means of pump chamber cover 51 and intermediate plate 52 whichseparates pump chamber from the gear housing 12. Impeller hub 35 isjournaled in suitable circular pockets 53 and 54 provided respectivelyin the faces of the pump chamber cover 51 and intermediate plate 52which face inwardly toward pump chamber 59. Circular pocket 54 is madesutliciently deep so that coupling washer 44 can be sandwiched thereinto couple impeller hub 35 with circular boss 39.

It will be noted from FIGURE 6 that gear housing 12, intermediate plate52 and pump chamber cover 51 are integrated into a unitary assembly bymeans of machine screws 55 which penetrate holes provided in gearhousing 12 and intermediate plate 52 and threadably engage with pumpchamber cover 51 to provide a fluid-tight seal for pump chamber 50.O-ring 56 is employed in cooperation with suitable grooves positioned inmating faces of intermediate plate 52 and pump chamber cover 51, toprovide a fluid-tight pump chamber. The inner hole 57 provided inintermediate plate 52 through which circular boss 39 extends is madefluid-tight by means of a conventional oil seal 58 which cooperates withthe side wall of hole 57 and circular boss 39.

The pumping element positioned in pump chamber 50 comprises two opposedimpeller vanes 66 and 66 mounted in side-by-side relationship within adiametrical slot 67 provided in impeller hub 35. The impeller vanes 66and 66' are biased outwardly and urged into abutment with the side wallof pump chamber 50 by means of compression coil spring 68 which ismounted within the common slot formed by the cooperating elongated slots69 and 69' provided respectively in impeller vanes 66 and .66. in FIGURE7, it will be seen that impeller vanes 66 and 66' are identically formedwith slots 69 and 69 being closer to one end of the vane than the other.Thus, when the impeller vanes 66 and 66 are placed in an opposedposition, the resulting common slot which holds coiled compressionspring 68 can be changed in length from a length equivalent to thelength of one of the slots in the impeller vanes or smaller. Thus, withcompression coil spring 68, which is longer than the impeller slot,engaging the opposed edges of slots 69 and 69, the impeller vanes 66 and66 are urged outwardly against the side wall of pump chamber 50. In theillustrated embodiment, the pumping efliciency of the pump is enhancedby providing a coil spring which causes the impeller vanes to exert a 1/-3 /z pounds force against the sidewall of the pump chamber. During thecourse of the rotation of impeller vanes 66 and 66 over the depressedarea 70 surrounding the outlet port 71, they are retained in correctorbit by the portions and 76 of the side wall which surrounds depressedarea 70.

In order to effectuate the objectives of this invention, impeller hub 35is eccentrically mounted in pump chamber 50 in tangential contact withthe side wall 60 of pump chamber 50 as shown in FIGURE 5 such that asubstantially fluid-tight barrier is provided at this null point. Inorder to produce the desired mistiming of the pumping cycle, inlet port61 is angularly displaced from the point of tangential contact toproduce a surge area 62 which, during the operation of the pump,produces pulsations which are transmitted through the substantiallyrigid conduit employed as the inlet line 63 connected to the pump inlet64 by means of a conventional tubing coupling means 65. In theillustrated embodiment the angular displacement is 32. Generally anangular displacement of 2540 is used; however, angles outside this rangecan be used. During the operation of the pump, as the impeller vane 66passes the point of tangential contact and traverses the surge area 62,there is produced a sub-atmospheric pressure within this area. When theinlet port 61 is opened by impeller vane 66 passing the edge of inletport 61 adjacent the surge area 62, the sub-atmospheric pressure isinstantaneously in creased to the pressure existing in the inlet 64 ofthe pumping unit. This produces a resulting surge or pulse which, whenproduced at the frequency of rotation of the pump, causes a vibrationalenergy wave. The energy produced when transmitted to the sump by asuitable means such as a rigid conduit is sufficient to maintain the oilwithin the sump in a state of agitation and minimize the settling ofsludge particles during the draining of the oil from the sump. Anysludge particles which are carried through inlet 64 into pump chamber 50are swept out of pump chamber 50 by impeller vane 65 in cooperation withthe depressed area 70 surrounding outlet port 71 which communicates withpump outlet 72. A suitable discharge line 73 is connected to outlet 72by a coupling means '74, as shown. Accordingly, the depressed areasurrounding outlet port 71 prevents any solid sludge particles frombeing trapped in pump chamber 50 and driven into the point of tangentialcontact between the impeller hub 35 and the pump chamber cover 51 whichwould result in the jamming of the impeller hub 35 and prevent its freerotation. This area also acts as an oil reservoir and during periodswhen the pump is not functioning will hold enough oil to insure the selfpriming of the pump upon restarting. To obtain this desired effect thepump unit should be so positioned to avoid the complete gravity drainageof the residual oil from this area.

An illustrative application of the sump drainage unit of this inventionas installed on an automotive vehicle is schematically shown in FIGURE7. In this instance, the sump drainage unit 80 is mounted on the motorblock of engine 81 by suitable brackets. The inlet line 82 is asubstantially rigid conduit connected to the outlet 83 of crankcase 84.Preferably a T-fitting is employed with the side outlet thereof beingconnected to the outlet 83 in crankcase 84. A removable plug (not shown)is litted at one end of the run of the T-fitting. The other end of therun is connected directly to inlet line 82. Outlet line 85, which can beany suitable rigid or non-rigid tubing or conduit, is led to a suitableposition on the automobile chassis under which a container 86 can beplaced and into which the drained oil can be discharged. The electricalmotor 87 used to power the drainage unit 80 is connected to the carbattery 88 by suitable electrical leads and the pump 80 is energized bymeans of a keyoperated switch 88 (shown schematically) located on thedashboard in the operators compartment of the automobile. To avoidoperating the pump 80 while the automobile engine is operating or thecar is being driven, or conversely to prevent the engine from beingoperated with inadequate oil supply in the crankcase, an electricalinterlock system shown schematically in FIGURE 1 can be used. Thus, tooperate the pump 80, switch 88 is connected in series with the so-calledoff side of a conventional automotive ignition switch 39. Accordingly,when switch 89 is in the position which energizes the accessoryautomotive electrical circuit without energizing the ignition circuitswitch 88 can be used to operate motor 87, and thereby automaticallydrain the oil from the crankcase 90. Thereafter, the crankcase can berefilled with fresh oil by poring the oil through the crankcase filltube in the conventional manner. If desired, the electrical motor 87 canbe made reversible and means provided for pumping oil from a suitablecontainer through line 85 and into the crankcase 9% The other phase ofthe electrical interlock system will prevent the automo bile engine frombeing started while the crankcase is empty, by installing a suitablepressure-sensitive switch 91 in the crankcase 90 adjacent the lowestportion thereof. This switch 91 is sensitive to liquid level and will bedesigned to be in the closed position when the liquid level within thecrankcase 90 has lowered during the course of the oil draining.

Upon opening switch 91, the normally closed armature 92. of relay 93will interrupt the electrical continuity of the ignition circuit 94 bythe separation of electrical contacts 95 and 96. As a result of theopening of contacts 95 and 96, ignition switch 89 will be inoperativeand will thereby prevent the engine from being started while the oillevel in crankcase is at a low level.

Conventional materials of construction are used in fabricating thedrainage unit components. The various parts of the housing can bedie-cast from aluminum. The impeller can be made by powdered metallurgytechniques or conventional machining operations. Preferably the impellervanes are made from laminate plastics such as melamine orphenol-formaldehyde laminates employing a linen base. The pumping unitcan be driven by prime movers other than the electrical motor as shown.If an electrical motor is employed, a fractional horse power AC. or DC.motor is utilized. For example, in one specific embodiment of a sumpdrainage unit manufactured in accordance with this invention, a DC.series motor having A H.P. was employed. This motor was designed tooperate with a no-load rotation of 15,000 r.p.m. employing a l2-voltD.C. source of power. While pumping, the motor rot-ates at 10,000r.p.m., and will draw 2.5 to 3.5 amps. In employing this motor, a speedreduction unit was employed which provided a 72:1 reduction.Accordingly, the pump unit operated at a speed of -150 r.p.m. Thecapacity of the pump should be selected so that the drainage of the sumpcan be carried out within a short period of time. For example, in somedrainage units employed for automotive use, it is preferable to employ apump capacity of one liquid gallon per minute so that the oil drainagecan be carried out within a short period of time. In the event thatother prime movers are available as part of the equipment upon which thesump drainage unit of this invention is used, the pump can be coupled byconventional mechanical means thereto in order to eliminate the integralelectric motor as shown.

This application is a continuation-in-part of application Serial No.818,181, filed June 4, 1959, by Woodrow E. Hoch, now abandoned.

Although the subject invention has been described with reference to theaforementioned specific embodiment, it is apparent that variations andmodifications can be made by those skilled in the art without departingfrom the scope of the invention. Accordingly, it is intended that thesubject invention be limited only by the spirit of the invention asdefined in the appended claims.

What is claimed is:

l. A non-variable, rotary displacement pump for lubricating andindustrial oil drainage units which comprises a pump casing having asubstantially circular chamber surrounded by a straight sidewallfabricated from a single material of construction, a cylindricalimpeller hub eccentrically mounted within said chamber in tangential,substantially fluid-tight contact with said sidewall, said hub beingprovided with a diametrical slot, a pair of impeller vanes positioned insaid slot in side by side, sliding contact, said vanes being yieldablybiased outwardly into abutment with said sidewall, and an inlet portadjacent said tangential contact on one side thereof, the side Wall ofsaid inlet port adjacent said tangential contact being angularly spacedtherefrom to mistime said pumping cycle and induce pulsations on onlythe inlet side of said pump, and an outlet port in said sidewalladjacent said tangential contact on the other side thereof, said outletport being provided with a recessed cavity in said sidewall cooperatingwith and surrounding the opening in said outlet port, a portion of themarginal edge of said recessed cavity being immediately adjacent saidtangential contact.

2. A non-variable rotary displacement pump for lubricating andindustrial oil drainage units which comprises a pump casing having asubstantially circular chamber surrounded by a straight sidewallfabricated from a single material of construction, a pair of opposedclosure plates mounted in fluid-tight relationship on said sidewall toenclose said chamber, a cylindrical impeller hub eccentrical- 1y mountedwithin said chamber in tangential, substantially fluid-tight contactwith said sidewall and journalled in said closures, said hub beingprovided with a diametrical slot, a pair of impeller vanes positioned insaid slot in side by side sliding contact, said vanes being yicld ablybiased outwardly into abutment with said side-wall, and an inlet portadjacent said tangential contact on one side thereof, the side wall ofsaid inlet port adjacent said tangential contact being angularly spacedtherefrom to mistime said pumping cycle and induce pulsations on onlythe inlet side of said pump, and an outlet port in said sidewalladjacent said tangential contact on the other side thereof, said outletport being provided with a recessed cavity in said sidewall cooperatingwith and surrounding the opening in said outlet port, a portion of themarginal edge of said recessed cavity being immediately adjacent saidtangential contact.

3. A non-variable rotary displacement pump for lubricating andindustrial oil drainage units which comprises a pump casing having asubstantially circular chamber surrounded by a straight sidewallfabricated from a single material of construction, a pair of opposedclosure plates mounted in fluid-tight relationship on said sidewall toenclose said chamber, a cylindrical impeller hub eccentrically mountedwithin said chamber in tangential substantially fluid-tight contact withsaid sidewall and journalled in said closures, said hub being providedwith a diametrical slot, a pair of impeller vanes positioned in saidslot in side by side sliding contact, said vanes being yieldably biasedoutwardly into abutment with said sidewall, and an inlet port adjacentsaid tangential contact on one side thereof, the side wall of said inletport adjacent said tangential contact being angula-rly spaced therefromto mistime said pumping cycle and induce pulsations on only the inletside of said pump, an outlet port in said sidewall adjacent saidtangential contact on the other side thereof, said outlet port beingprovided with a recessed cavity in said sidewall cooperating with andsurrounding the opening in said outlet port a portion of the marginaledge of said recessed cavity being immediately adjacent said tangentialcontact; and a speed reduction drive means for said pump comprising areduction pinion pump drive gear, coupling means connecting saidimpeller hub and said pinion gear, a prime mover, and gear means drivenby said prime mover and cooperating with said pinion gear to elfect itsrotation at a slower speed than the speed of rotation of said primemover.

l. A unitary drainage unit for lubricating oils and industrial oilswhich comprises a pump casing having a substantially circular chambersurrounded by a straight side wall fabricated from a single material ofconstruction, a pair of opposed closure plates mounted in fluid-tightrelationship on said sidewall to enclose said chamber, an impeller hubeccentrically mounted within said chamber in tangential, substantially-fluid-tight contact with said sidewall and journalled in said closures,said hub being provided with a diametrical slot, a pair of impellervanes positioned in said slot in side by side sliding contact, saidvanes being yieldably biased outwardly into abutment with said sidewall,and an inlet port adjacent said tan- ;gential contact on one sidethereof, the side wall of said inlet port adjacent said tangentialcontact being angularly spaced therefrom to mistime said pumping cycleand induce pulsations on only the inlet side of said pump, and an outletport in said sidewall adjacent said tangential contact on the other sidethereof, said outlet port being provided with a recessed cavity in saidsidewall cooperating with and surrounding the opening in said outletport a portion of the marginal edge of said recessed cavity beingimmediately adjacent said tangential contact, bracket means dependingfrom said pump casing; an electrical motor fastened to said pump meanswith the longitudinal axis of said motor being normal to the axis ofrotation of said impeller hub; and a speed reduction drive means forsaid pump comprising a reduction pinion pump drive gear, C upling meansconnecting said impeller hub and 8 said pinion gear, and a housingenclosing said pinion gear, a worm gear journalled in said housing andmeshing with said pinion gear, and coupling means rotatably connectingsaid worm gear with said motor.

5. An oil sump drainage system which comprises an oil sump provided witha drainage outlet disposed adjacent the bottom thereof, a non-variablerotary displacement pump comprising a pump casing having a substantiallycircular chamber surrounded by a sidewall, an impeller hub eccentricallymounted within said chamber in tangential, substantially fluid-tightcontact with said sidewall, said hub being provided with a diamctricalslot, a pair of impeller vanes positioned in said slot in side by sidesliding contact, said vanes being yieldably biased outwardly intoabutment 'with said sidewall, and an inlet port adjacent said tangentialcontact on one side thereof, the side wall of said inlet port adjacentsaid tangential contact being angularly spaced therefrom to mistime saidpumping cycle and induce pulsations on only the inlet side of said pump,and an outlet port in said sidewall adjacent said tangential contact onthe other side thereof, said outlet port being provided with a recessedcavity in said sidewall cooperating with and surrounding the opening insaid outlet port, a portion of the marginal edge of said recessed cavitybeing immediately adjacent said tangential contact, rigid conduit meansinterconnecting said drainage outlet and said inlet port, and conduitmeans connected to said outlet port for discharging oil from said sump.

6. An oil sump drainage system which comprises a sump provided with adrainage outlet disposed adjacent the bottom thereof, a non-variablerotary displacement pump comprising a pump casing having a substantiallycircular chamber surrounded by a sidewall, a pair of opposed closureplates mounted in fluid-tight relationship on said sidewall to enclosesaid chamber, an impeller hub eccentrically mounted within said chamberin tangential substantially fluid-tight contact with said sidewall andjournalled in said closures, said hub being provided with a diametricalslot, a pair of impeller vanes positioned in said slot in side by sidesliding contact, said vanes being yieldably biased outwardly intoabutment with said sidewall, and an inlet port adjacent said tangentialcontact on one side Lhereof, the side wall of said inlet port adjacentsaid tangential contact being angularly spaced therefrom to mistime saidpumping cycle and induce pulsations on only the inlet side of said pump,and an outlet port in said sidewall adjacent said tangential contact onthe other side thereof, said outlet port being provided with a recessedcavity in said sidewall cooperating with and surrounding the opening insaid outlet port, a portion of the marginal edge of said recessed cavitybeing immediately adjacent said tangential contact; rigid conduit meansinterconnecting said drainage outlet and said inlet port, and conduitmeans connected to said outlet port for discharging oil from said sumpand a speed reduction drive means for said pump comprising a reductionpinion drive gear, coupling means connecting said impeller hub and saidpinion gear, a prime mover, and gear means riven by said prime mover andcooperating with said pinion gear to effect its rotation at a slowerspeed than the speed of rotation of said prime mover.

7. An oil sump drainage system which comprises an oil sump provided witha drainage outlet disposed adjacent the bottom thereof, a non-variablerotary displacement pump which comprises a pump casing having asubstantially circular chamber surrounded by a sidewall, a pair ofopposed closure plates mounted in fluid-tight relationship on saidsidewall to enclose said chamber, an impeller hub eccentrically mountedwithin said chamber in tangential, substantially fluid-tight contactwith said sidewall and journalled in said closures, said hub beingprovided with a diametrical slot, a pair of impeller vanes positioned insaid slot in side by side sliding contact, said vanes being yieldablybased outwardly into abutment with said sidewall, and an inlet portadjacent said tangential contact on one side thereof, the side wall ofsaid inlet port adjacent said tangential contact being angularly spacedtherefrom to mistime said pumping cycle and induce pulsations on onlythe inlet side of said pump, and an outlet port in said sidewalladjacent said tangential contact on the other side thereof, said outletport being provided with a recessed cavity in said sidewall cooperatingwith and surrounding the opening in said outlet port, a portion of themarginal edge of said recessed cavity being immediately adjacent saidtangential contact, an electric motor for driving said pump, a source ofelectrical power for said motor, and electrical switch means forcontrolling the distribution of electrical power to said motor, a liquidlevel sensing means communicating with the interior of said sump,electrical relay means actuated by said liquid level sensing means, saidelectrical relay means being connected in series with an engineelectrical circuit whereby said engine circuit 10 is incapable of beingenergized at low liquid levels in said sump.

References Cited in the file of this patent UNITED STATES PATENTS256,781 Winkler Apr. 18, 1882 1,329,895 Frodsham Feb. 3, 1920 1,339,723Smith 'May 11, 1920 1,938,854 Mon-let Dec. 12, 1933 1,960,389 MoFerran HMay 29, 1934 2,250,271 Morgan July 22, 1941 2,260,312 Gruman Oct. 28,1941 2,312,886 Ellin-wood Mar. 2, 1943 2,367,326 Beckman Jan. 16, 19452,717,770 Gibson et al. Sept. 13, 1955 FOREIGN PATENTS 703,047 GreatBritain I an. 27, 1954 1,072,018 France Mar. 10, 1954

1. A NON-VARIABLE, ROTARY DISPLACEMENT PUMP FOR LUBRICATING ANDINDUSTRIAL OIL DRAINAGE UNITS WHICH COMPRISES A PUMP CASING HAVING ASUBSTANTIALLY CIRCULAR CHAMBER SURROUNDED BY A STRAIGHT SIDEWALLFABRICATED FROM A SINGLE MATERIAL OF CONSTRUCTION, A CYLINDRICALIMPELLER HUB ECCENTRICALLY MOUNTED WITHIN SAID CHAMBER IN TANGENTIAL,SUBSTANTIALLY FLUID-TIGHT CONTACT WITH SAID SIDEWALL, SAID HUB BEINGPROVIDED WITH A DIAMETRICAL SLOT, A PAIR OF IMPELLER VANES POSITIONED INSAID SLOT IN SIDE BY SIDE, SLIDING CONTACT, SAID VANES BEING YIELDABLYBIASED OUTWARDLY INTO ABUTMENT WITH SAID SIDEWALL, AND AN INLET PORTADJACENT SAID TANGENTIAL CONTACT ON ONE SIDE THEREOF, THE SIDE WALL OFSAID INLET PORT ADJACENT SAID TANGENTIAL CONTACT BEING ANGULARLY SPACEDTHEREFROM TO MISTIME SAID PUMPING CYCLE AND INDUCE PULSATIONS ON ONLYTHE INLET SIDE OF SAID PUMP, AND AN OUTLET PORT IN SAID SIDEWALLADJACENT SAID TANGENTIAL CONTACT ON THE OTHER SIDE THEREOF, SAID OUTLETPORT BEING PROVIDED WITH A RECESSED CAVITY IN SAID SIDEWALL COOPERATINGWITH AND SURROUNDING THE OPENING IN SAID OUTLET PORT, A PORTION OF THEMARGINAL EDGE OF SAID RECESSED CAVITY BEING IMMEDIATELY ADJACENT SAIDTANGENTIAL CONTACT.